Organopolysiloxanes find use as textile treating agents, parting agents, water repellents, and cosmetics since substrates can be endowed with smoothness and water repellency by treating them with organopolysiloxanes. Among others, high-viscosity organopolysiloxanes are quite effective for imparting smoothness. Due to the recent enhanced concern about the environment, there are an increasing tendency to use aqueous treating agents and an increasing demand for stable emulsions of high-viscosity organopolysiloxanes. However, the high-viscosity organopolysiloxane has so high a viscosity that no mechanical shears may be uniformly applied. It is thus impossible to form a stable emulsion from the high-viscosity organopolysiloxane. Several methods of producing high-viscosity organopolysiloxane emulsions are known from Patent Documents 1 to 3, but not generally acceptable because they need a special emulsifying technique or device.